At Cape Hatteras National Seashore in North Carolina, Sara has developed a talk about pirates for visitors. At Mesa Verde National Park in Colorado, Bruce has shared expertise on North American Indian migration.

Punching the clock at one of the country's many national parks, monuments and historic sites can be a great option for retirees and people facing layoffs. It's generally seasonal work, as the park bulks up its staff for peak times of year.

The National Park Service and its $1-billion-a-year concession industry rely on thousands of seasonal employees for everything from giving ranger talks about history and nature to manning the entry gates to shuttling employees from housing to work. And that housing — cabins, dormitories, apartments or RV spots – often is a perk that comes with the job.

Nearly a third of the national park workforce is over the age of 50, a "priceless" resource for the agency that protects the nation's most revered places, says Park Service Director Jonathan B. Jarvis.

"Imagine. People with advanced degrees, 30 or more years in careers as engineers, teachers, lawyers, doctors, accountants, fire fighters, police officers, you name it … and they want to work in a national park," Jarvis told AARP. "They provide amazing programs for visitors."

Thousands of park positions don't require experience, especially those with the 497 park concessioners — private contractors operating park services such as restaurants and lodging, river rafting and bus tours.